Electrostatic coupling friction spinning device and preparation method of cross-scale core-spun yarn

Abstract

This invention relates to an electrostatic coupling friction spinning device, comprising a spinning system controlled by a CNC system. The spinning system includes a yarn guiding mechanism, a yarn feeding mechanism, and a take-up mechanism. The yarn guiding mechanism includes a yarn bobbin wound with core yarn, an inlet yarn guide hook, an inlet yarn guide roller and a yarn guide skin roller, a pair of friction rollers, an outlet yarn guide roller and a yarn guide skin roller, and an outlet yarn guide hook, arranged sequentially. The yarn feeding mechanism includes an electrostatic coupling device located at the bottom of the friction rollers for generating nanofibers and a suction device located at the top of the friction rollers. The take-up mechanism includes a grooved cylinder and a yarn tube located above the outlet yarn guide hook. This invention uses an electrostatic coupling device to produce nanofibers and positions the twisting of the fibers below the friction rollers. This cleverly utilizes the twisting device to achieve the orientation and aggregation of nanofibers, enabling the friction spinning machine to produce high-value-added products while simultaneously solving problems such as low coverage rate, poor orientation, and low yarn preparation efficiency in cross-scale core-spun yarns.

Description

Technical Field

[0001] This invention belongs to the field of textile processing technology, and in particular relates to an electrostatic coupling friction spinning device and a method for preparing cross-scale core-spun yarn. Background Technology

[0002] Besides traditional ring spinning, spinning technology also includes new spinning technologies such as compact spinning, Siro spinning, rotor spinning, air-jet spinning, air-jet vortex spinning, friction spinning, and self-twisting spinning. Friction spinning, invented by Dr. Ferrer of Austria in 1973 and gradually improved, is a novel spinning method that combines aerodynamics and mechanics. It achieves fiber adsorption and cohesion while simultaneously using the rotational motion of the sliver and friction components to twist the yarn. Friction spinning machines include DREF I, DREF II, and DREF III types. The DREF III type is mainly used for producing core-spun yarn and consists of two sets of feeding and drafting mechanisms and a pair of dust cage twisting mechanisms. The first feeding and drafting mechanism is a four-up, four-down double-rubber roller drafting device. A sliver is fed in here, drafted, and then fed into the twisting zone of the dust cage to form the core yarn. The fibers fed in by the second drafting device are opened by the combing rollers and then wrapped around the core yarn as outer fibers to form the core-spun yarn.

[0003] Friction-spun yarns have a high twist in the inner layer and a low twist in the outer layer, resulting in a tight inner layer and a loose outer layer, with more hairiness and lower strength, limiting their products to coarse, medium, and low-density yarns. Friction spinning has a wide range of applications, especially in producing various core-spun yarns, such as multifilament, monofilament, spandex, and metallic yarns, each with its own characteristics. In contrast, traditional ring-spun core-spun yarns have extremely high core yarn density requirements, generally using fine elastic yarns; otherwise, they are prone to showing white spots. Other new spinning technologies, such as rotor spinning and air-jet spinning, are still under development for producing core-spun yarns.

[0004] Traditional methods for preparing multi-scale core-spun yarns, such as mechanical rotation twisting, water bath twisting, and airflow twisting, still have shortcomings in terms of nanofiber coverage, orientation, and yarn preparation efficiency. Mechanical rotation twisting utilizes nanofiber deposition on a metal device surface, with twisting achieved through the combined action of collector rotation and yarn drafting. Currently, collectors such as discs, metal trumpets, and metal spiral targets are commonly used in conjunction with conjugate bundling to prepare core-spun yarns. Conjugate bundling utilizes the aggregation effect of oppositely charged tips and the attraction effect of opposite charges to achieve the orientation deposition and aggregation of nanofibers into yarn. However, this method relies on a single-needle nozzle to supply nanofibers, making it difficult to improve yarn yield. Water bath twisting involves depositing nanofibers in a liquid coagulation bath, while simultaneously twisting the yarn through the vortex formed by the liquid. However, this method results in low fiber orientation, uneven morphology, uncontrollable yarn twist, and the risk of cross-contamination from the water bath. Airflow twisting primarily utilizes the trajectory of rotating airflow to guide yarn twisting. However, the combined effect of airflow and electric field is quite complex. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an electrostatic coupling friction spinning device and a method for preparing cross-scale core-spun yarn, which improves the orientation and aggregation of nanofibers and solves the problems of low coverage, poor orientation and low yarn preparation efficiency of cross-scale core-spun yarn.

[0006] The technical solution adopted by the present invention to solve its technical problem is as follows: An electrostatic coupling friction spinning device is provided, comprising a spinning system controlled by a CNC system. The spinning system includes a yarn guiding mechanism, a yarn feeding mechanism, and a winding mechanism. The yarn guiding mechanism includes a yarn bobbin wound with core yarn, an inlet yarn guiding hook, an inlet yarn guiding roller and a yarn guiding skin roller, a pair of friction rollers, an outlet yarn guiding roller and a yarn guiding skin roller, and an outlet yarn guiding hook arranged sequentially. The yarn feeding mechanism includes an electrostatic coupling device located at the bottom of the friction rollers for generating nanofibers and a suction device located at the top of the friction rollers. The winding mechanism includes a grooved cylinder and a yarn tube located above the outlet yarn guiding hook.

[0007] Preferably, the spinning system is housed inside a box, and the CNC system is located on one side of the box. The surface of the CNC system is equipped with a touch screen, a start button, and a stop button. The CNC system contains a PLC, which can control the rotational speed of the inlet guide roller and guide roller, a pair of friction rollers, the outlet guide roller and guide roller, and the groove cylinder. The PLC also controls the suction speed of the suction device and the excitation speed of the electrostatic coupling device.

[0008] Preferably, the inlet yarn guide hook, the slit groove between the inlet yarn guide roller and the yarn guide skin roller, the lower slit groove of the friction roller, the slit groove between the outlet yarn guide roller and the yarn guide skin roller, and the outlet yarn guide hook are all located on the same horizontal plane.

[0009] Preferably, the two friction rollers are arranged horizontally, the core yarn passes between the two friction rollers, the tail end of each friction roller is provided with a bearing, and the two bearings are connected by a belt.

[0010] Preferably, the air intake of the suction device is located directly above the friction roller, and the fiber outlet of the electrostatic coupling device is located directly below the lower slit groove of the two friction rollers.

[0011] Preferably, the electrostatic coupling device includes a high-voltage generator, a liquid supply device, a spherical nozzle, and a cylindrical base. The positive electrode of the high-voltage generator is connected to the spherical nozzle, and the high-voltage adjustment range is 0-120kV. The liquid supply device is connected to the spherical nozzle. The spherical nozzle is made of solid stainless steel, and the cylindrical base is made of solid polytetrafluoroethylene.

[0012] This invention also provides a method for preparing cross-scale core-spun yarn, using the above-mentioned electrostatic coupling friction spinning device, comprising the following steps:

[0013] S1. Add the polymer to a solvent and stir to prepare a spinning solution, and add the spinning solution to an electrostatic coupling device;

[0014] S2. The core yarn is drawn out from the yarn bobbin, passes through the inlet guide hook, and is fed into the slit groove between the inlet guide roller and the guide roller. It passes through the lower slit groove of the two friction rollers, then through the slit groove between the outlet guide roller and the guide roller, passes through the outlet guide hook, and is wound onto the yarn tube driven by the grooved drum.

[0015] S3. Set the operating parameters of the spinning system on the touch screen, press the start button, run the yarn guiding mechanism and make both friction rollers rotate in the same direction at high speed.

[0016] S4. Start the electrostatic coupling device to excite the spinning solution to obtain nanofibers. Start the suction device to attract the nanofibers upward and deposit them as skin fibers onto the lower slit grooves of the two friction rollers. The nanofibers are twisted onto the core yarn transported by the yarn guiding mechanism by the high-speed rotation of the two friction rollers in the same direction to obtain cross-scale core-spun yarn. The cross-scale core-spun yarn is wound onto the yarn tube through the exit guide roller, the guide roller, and the exit guide hook.

[0017] In S1, the polymer is polyacrylonitrile powder, the solvent is N,N-dimethylformamide, and the spinning solution is prepared with a polyacrylonitrile mass fraction of 10% to 15%. The core yarn is a common single yarn or ply yarn, such as polyester-cotton blended yarn or pure cotton yarn.

[0018] In step S3, the operating parameters of the spinning system include a feed speed of 1.5–7.33 m / min, a drafting speed of 1.55–7.33 m / min, a crimping speed of 1.70–7.4 m / min, and a friction roller speed of 300–1480 rpm.

[0019] In step S4, the high voltage adjustment range of the electrostatic coupling device is set to 30-70kV, and the vertical distance adjustment range between the electrostatic coupling device and the friction roller is set to 8-60cm.

[0020] Beneficial effects

[0021] This invention uses an electrostatic coupling device to produce nanofibers, replacing the combing component of a traditional spinning machine. It also changes the twisting position of the fibers from above the friction roller to below, cleverly utilizing the twisting device to achieve the orientation and aggregation of nanofibers. This enables the friction spinning machine to produce high-value-added products such as fine yarns, and also solves prominent problems such as low coverage rate, poor orientation, and low yarn preparation efficiency in cross-scale core-spun yarns. Attached Figure Description

[0022] Figure 1This is a schematic diagram of an electrostatic coupling friction spinning device.

[0023] Figure 2 An electron microscope image of Example 1 of a polyacrylonitrile nanofiber / polyester-cotton blended core-spun yarn produced by an electrostatic coupling friction spinning device.

[0024] Figure 3 Electron micrograph of Example 2 of polyacrylonitrile nanofiber / polyester-cotton blended core-spun yarn produced by an electrostatic coupling friction spinning device.

[0025] Among them, 1-box body; 2-CNC system; 3-touch display screen; 4-start button; 5-stop button; 6-yarn tube; 7-core yarn; 8-inlet guide hook; 9, 10-inlet guide roller and guide roller; 11-friction roller; 12-belt; 13-electrostatic coupling device; 14-nanofiber; 15-suction device; 16, 17-outlet guide roller and guide roller; 18-cross-scale core-spun yarn; 19-outlet guide hook; 20-groove drum; 21-yarn tube.

[0026] The same markings in each diagram represent the same component. Detailed Implementation

[0027] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0028] This invention provides an electrostatic coupling friction spinning device, comprising a spinning system controlled by a CNC system. The spinning system includes a yarn guiding mechanism, a yarn feeding mechanism, and a winding mechanism. The yarn guiding mechanism includes a yarn bobbin wound with core yarn, an inlet yarn guide hook, an inlet yarn guide roller and a yarn guide skin roller, a pair of friction rollers, an outlet yarn guide roller and a yarn guide skin roller, and an outlet yarn guide hook arranged in sequence. The yarn feeding mechanism includes an electrostatic coupling device at the bottom of the friction rollers for generating nanofibers and a suction device at the top of the friction rollers. The winding mechanism includes a grooved cylinder and a yarn tube located above the outlet yarn guide hook.

[0029] The electrostatic coupling device used in this invention is existing technology, comprising a high-voltage generator, a liquid supply device, a spherical nozzle, and a cylindrical base. The positive terminal of the high-voltage generator is connected to the spherical nozzle, and the high-voltage adjustment range is 0–120 kV. The liquid supply device is connected to the spherical nozzle, which is made of solid stainless steel, and the cylindrical base is made of solid polytetrafluoroethylene. This device can excite and spray spinning solution to form nanofibers.

[0030] In one specific embodiment, such as Figure 1 As shown, the spinning system is housed inside a box. The CNC system is located on one side of the box. The surface of the CNC system is equipped with a touch-screen display, a start button, and a stop button. The CNC system contains a PLC, which can control the rotational speed of the inlet guide roller and guide roller, a pair of friction rollers, the outlet guide roller and guide roller, and the grooved cylinder. The PLC also controls the suction speed of the suction device and the excitation speed of the electrostatic coupling device.

[0031] The inlet yarn guide hook, the slit groove between the inlet yarn guide roller and the yarn guide skin roller, the lower slit groove of the friction roller, the slit groove between the outlet yarn guide roller and the yarn guide skin roller, and the outlet yarn guide hook are all located on the same horizontal plane.

[0032] The two friction rollers are arranged horizontally, and the core yarn passes between them. The transmission device for the friction rollers includes a bearing located at the tail end of each roller, which is connected to a motor located outside the housing via a belt. The transmission system is a conventional design and is not shown in the accompanying drawings. The motor drives the belt to make the friction rollers rotate continuously in the same direction at high speed. Here, "rotating in the same direction" means that when looking from the side of the inlet guide roller and guide skin roller towards the side of the outlet guide roller and guide skin roller, the left friction roller rotates clockwise and the right friction roller rotates counterclockwise.

[0033] The air intake of the suction device is located directly above the friction roller, and the fiber outlet of the electrostatic coupling device is located directly below the lower slit grooves of the two friction rollers.

[0034] The following examples illustrate the usage of the present invention in detail. Example 1:

[0035] 12.94g of polyacrylonitrile powder was added to 100ml of N,N-dimethylformamide and stirred to prepare a spinning solution with a polyacrylonitrile mass fraction of 12%. The spinning solution was then added to an electrostatic coupling device.

[0036] The polyester-cotton blended yarn is drawn out from the yarn bobbin, passes through the inlet guide hook, and is fed into the slit groove between the inlet guide roller and the guide roller. It passes through the lower slit groove of the two friction rollers, then through the slit groove between the outlet guide roller and the guide roller, passes through the outlet guide hook, and is wound onto the yarn tube driven by the grooved drum.

[0037] Access the parameter interface on the touch screen, set the operating parameters of the spinning system: feed speed 1.5m / min, drafting speed 1.55m / min, friction roller speed 300r / min, winding speed 1.7m / min, press the start button, run the yarn guiding mechanism and make the two friction rollers rotate in the same direction at high speed.

[0038] The vertical distance between the electrostatic coupling device and the friction roller is set to 8 cm, the applied voltage is 50 kV, the ambient temperature is 19.6℃, and the ambient humidity is 47%. When the switch is turned on, the device excites the spinning solution to obtain nanofibers. The nanofibers are deposited on the lower slit grooves of the two friction rollers. The nanofibers are twisted onto the core yarn by the high-speed rotation of the two friction rollers in the same direction to obtain polyacrylonitrile nanofiber / polyester-cotton blended core-spun yarn. The core-spun yarn passes through the guide roller, guide roller skin, and guide hook, and is finally wound onto the yarn tube through the grooved drum.

[0039] Electron micrographs of the produced polyacrylonitrile nanofiber / polyester-cotton blended core-spun yarn are shown below. Figure 2 As shown, a) is an electron microscope image of the surface morphology of the core yarn (polyester-cotton blended yarn), b) is an electron microscope image of the surface morphology of the polyacrylonitrile nanofiber / polyester-cotton blended core-spun yarn, and c) and d) are electron microscope images of the polyacrylonitrile nanofiber / polyester-cotton blended core-spun yarn at 400x magnification and 1000x cross-sectional magnification, respectively.

[0040] Example 2:

[0041] This embodiment provides an electrostatic coupling friction spinning device and a method for preparing cross-scale core-spun yarn. The specific steps are as follows:

[0042] 15.44g of polyacrylonitrile powder was added to 100ml of N,N-dimethylformamide and stirred to prepare a spinning solution with a polyacrylonitrile mass fraction of 14%. The spinning solution was then added to an electrostatic coupling device.

[0043] The polyester-cotton blended yarn is drawn out from the yarn bobbin, passes through the inlet guide hook, is fed into the slit groove between the inlet guide roller and the guide roller, passes through the lower slit groove of the two friction rollers, then passes through the slit groove between the outlet guide roller and the guide roller, passes through the outlet guide hook, and is wound onto the yarn tube driven by the grooved drum.

[0044] Access the parameter interface on the touch screen, set the operating parameters of the spinning system: feed speed 1.82 m / min, drafting speed 1.86 m / min, friction roller speed 600 r / min, and winding speed 2.04 m / min. Press the start button to run the yarn guiding mechanism and make the two friction rollers rotate in the same direction at high speed.

[0045] The vertical distance between the electrostatic coupling device and the friction roller is set to 11cm, the applied voltage is 45kV, the ambient temperature is 23.3℃, ​​and the ambient humidity is 48%. When the switch is turned on, the device excites the spinning solution to obtain nanofibers. The nanofibers are deposited on the lower slit grooves of the two friction rollers. The nanofibers are twisted onto the core yarn by the high-speed rotation of the two friction rollers in the same direction to obtain polyacrylonitrile nanofiber / polyester-cotton blended core-spun yarn. The core-spun yarn passes through the exit guide roller, the guide roller, and the exit guide hook, and is then wound onto the yarn tube through the grooved drum.

[0046] Electron micrograph of polyacrylonitrile nanofiber / polyester-cotton blended core-spun yarn produced using existing technology is shown below. Figure 3 As shown, a) is an electron microscope image of the surface morphology of polyester / polyester-cotton blended core-spun yarn produced using a conventional friction spinning machine, and b), c) and d) are electron microscope images of the surface morphology of polyacrylonitrile nanofiber / polyester-cotton blended core-spun yarn produced using an electrostatic coupling friction spinning machine at 400x, 1000x and 8000x magnification, respectively.

Claims

1. An electrostatic coupling friction spinning device, comprising a spinning system controlled by a numerical control system, characterized in that, The spinning system includes a yarn guiding mechanism, a yarn feeding mechanism, and a winding mechanism. The yarn guiding mechanism includes a yarn bobbin wound with core yarn, an inlet yarn guiding hook, an inlet yarn guiding roller and a yarn guiding leather roller arranged in sequence, a pair of friction rollers, an outlet yarn guiding roller and a yarn guiding leather roller, and an outlet yarn guiding hook. The yarn feeding mechanism includes an electrostatic coupling device located at the bottom of the friction roller for generating nanofibers and a suction device located at the top of the friction roller. The winding mechanism includes a grooved cylinder and a yarn tube located above the yarn guide hook at the output end. The inlet yarn guide hook, the slit groove between the inlet yarn guide roller and the yarn guide skin roller, the lower slit groove of the friction roller, the slit groove between the outlet yarn guide roller and the yarn guide skin roller, and the outlet yarn guide hook are all located on the same horizontal plane. The air intake of the suction device is located directly above the friction roller, and the fiber outlet of the electrostatic coupling device is located directly below the lower slit grooves of the two friction rollers.

2. The electrostatic coupling friction spinning device according to claim 1, characterized in that, The spinning system is housed inside a box. The CNC system is located on one side of the box. The surface of the CNC system is equipped with a touch screen, a start button, and a stop button. The CNC system contains a PLC, which can control the rotational speed of the inlet guide roller and guide roller, a pair of friction rollers, the outlet guide roller and guide roller, and the grooved cylinder. The PLC also controls the suction speed of the suction device and the excitation speed of the electrostatic coupling device.

3. The electrostatic coupling friction spinning device according to claim 1, characterized in that, The electrostatic coupling device includes a high-voltage generator, a liquid supply device, a spherical nozzle, and a cylindrical base. The positive terminal of the high-voltage generator is connected to the spherical nozzle, and the high-voltage adjustment range is 0~120kV. The liquid supply device is connected to the spherical nozzle. The spherical nozzle is made of solid stainless steel, and the cylindrical base is made of solid polytetrafluoroethylene.

4. A method for preparing cross-scale core-spun yarn, characterized in that, The electrostatic coupling friction spinning apparatus as described in any one of claims 1 to 3 includes the following steps: S1. Add the polymer to a solvent and stir to prepare a spinning solution, and add the spinning solution to an electrostatic coupling device; S2. The core yarn is drawn out from the yarn bobbin, passes through the inlet guide hook, and is fed into the slit groove between the inlet guide roller and the guide roller. It passes through the lower slit groove of the two friction rollers, then through the slit groove between the outlet guide roller and the guide roller, passes through the outlet guide hook, and is wound onto the yarn tube driven by the grooved drum. S3. Set the operating parameters of the spinning system on the touch screen, press the start button, run the yarn guiding mechanism and make both friction rollers rotate in the same direction at high speed. S4. Start the electrostatic coupling device to excite the spinning solution to obtain nanofibers. Start the suction device to attract the nanofibers upward and deposit them as skin fibers onto the lower slit grooves of the two friction rollers. The nanofibers are twisted onto the core yarn transported by the yarn guiding mechanism by the high-speed rotation of the two friction rollers in the same direction to obtain cross-scale core-spun yarn. The cross-scale core-spun yarn is wound onto the yarn tube through the exit guide roller, the guide roller, and the exit guide hook.

5. The method for preparing a multi-scale core-spun yarn according to claim 4, characterized in that, In step S1, the polymer is polyacrylonitrile powder, the solvent is N,N-dimethylformamide, and the spinning solution is prepared with a polyacrylonitrile mass fraction of 10%~15%. The core yarn is polyester-cotton blended yarn or pure cotton yarn, and the yarn type is ordinary single yarn or ply yarn.

6. The method for preparing a multi-scale core-spun yarn according to claim 4, characterized in that, In step S3, the operating parameters of the spinning system include a feed speed of 1.5~7.33 m / min, a drafting speed of 1.55~7.33 m / min, a crimping speed of 1.70~7.4 m / min, and a friction roller speed of 300~1480 rpm.

7. The method for preparing a multi-scale core-spun yarn according to claim 4, characterized in that, In step S4, the high voltage adjustment range of the electrostatic coupling device is set to 30~70kV, and the vertical distance adjustment range between the electrostatic coupling device and the friction roller is set to 8~60 cm.

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